Refractory compositions and method

ABSTRACT

Refractory compositions based upon alumina or aluminum silicate chemically bound by aluminum phosphate have a shelf life of three months to more than one year where the composition includes both liquid aluminum phosphate and phosphoric acid to form a portion of the aluminum phosphate binder in situ. In accordance with another embodiment of the present invention, increased strength is achieved by including alumina, and an aluminum silicate bearing material, such as clay, in the refractory composition to form the in situ aluminum phosphate bond from the reaction of phosphoric acid and aluminum silicate. The aluminum phosphate should be provided in the composition in an amount of about 5% to about 70% by weight of the bone dry composition and the phosphoric acid should be included in an amount in the range of about 1% to about 10% based on the weight of the bone dry composition to provide the surprisingly new and unexpected shelf life to the refractory composition. The aluminum phosphate and phosphoric acid together are particularly useful in a refractory ramming mix composition containing a heat insulator such as perlite, vermiculite, diatomaceous earth, expanded clay, flourspar, or an additive which is intended to be burned out to leave a void space at the intended use of the refractory, such as wood, flour, sawdust and the like.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional application of parent application Ser.No. 355,320 filed Mar. 8, 1982.

FIELD OF THE INVENTION

The present invention relates to chemically bonded refractorycompositions and method and more particularly relates to chemicallybonded refractory ramming mix compositions including an aluminumphosphate binder a portion of which forms in situ to provide a strong,chemically bonded, refractory composition. The refractory composition isparticularly useful for linings in furnaces, hot metal ladles and otheruses well known in the refractory art, particularly where hightemperatures above 1500-2000° F. are encountered. In accordance with oneembodiment of the present invention, an insulating material, such asperlite, vermiculite or diatomaceous earth is included in thecomposition to provide greater heat insulating resistance to therefractory composition, while retaining unexpectedly good strength priorto ceramic bond formation. The refractory compositions of the presentinvention have unexpectedly long shelf lives and increased strengthwhile in the plastic or wet state.

In accordance with another embodiment of the present invention, a dry,basic refractory material based upon magnesium oxide forms an in situmagnesium aluminum phosphate bond upon addition of water.

BACKGROUND OF THE INVENTION

Refractory ramming mix compositions containing a relatively highpercentage of alumina chemically bound by phosphoric acid or an aluminumphosphate are well known in the art, particularly as described in thefollowing patents: Salizar U.S. Pat. No. 3,547,664; Noda, et al. U.S.Pat. Nos. 3,958,582 and 3,891,009; Beeler U.S. Pat. No. 4,177,308; andErskine U.S. Pat. No. 4,248,810. In some of these patents, an insulatingmaterial, such as perlite, is included to provide a light, temperatureresistant refractory heat-insulating composition. The compositionsgenerally are mixed to the consistency of a paste or mortar consistencyso that the composition can be mixed, spread into a desired shape andsliced to form a slab of predetermined dimensions before the slices orslabs are rammed or pounded into place in a moist condition tophysically and chemically form a monolithic refractory lining. Thelining is then heated to drive off the moisture and heated at hightemperature to form the final set or ceramic bond necessary in arefractory lining.

As set forth in my prior U.S. Pat. No. 3,547,664, two of the biggestproblems in prior art high alumina ramming mixes are cracking upondrying and a need for higher strength at temperatures in which a mixmust relay upon a chemical bond before the ceramic bond is formed. Inaccordance with my prior patent, I found that including ceramic fibersin an amount of about 2-6% by weight of clay in the mix provides astronger ramming mix which does not crack upon drying.

Another problem with a prior art high alumina ramming mixes,particularly prevalent in chemically bound ramming mixes, is theinability to provide a ramming mix which has a shelf life of more thanabout three weeks. After a chemically bound ramming mix is sliced toform a slab of predetermined dimensions, the ramming mix begins to dryas a result of ambient conditions and, particularly, where a chemicalbinder such as aluminum phosphate is being formed in situ such asdescribed in my prior U.S. Pat. No. 3,547,664, where phosphoric acidreacts with alumina to form the aluminum phosphate binder. This in situreaction between phosphoric acid and alumina is exothermic resulting inmoisture being driven away from the ramming mix. The ramming mix must bemoist when rammed or pounded into position as a lining and, therefore,ramming mixes of the prior art generally have had a shelf life of aboutthree weeks or less. Liquid aluminum phosphate has been added as thechemical binder in some prior art refractory ramming mixes and,generally, since these refractory ramming mixes do not depend upon an insitu reaction for the formation of the aluminum phosphate binder, it hasbeen found that the shelf life problem is not as severe. However, noprior art refractory ramming mixes using a chemical binder will remainsufficiently wet for ramming or pounding into place significantly morethan about three weeks.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, suprisinglyit has been found that refractory compositions based upon alumina oraluminum silicate chemically bound by aluminum phosphate have a shelflife of three months to more than one year where the compositionincludes both liquid aluminum phosphate and phosphoric acid to form aportion of the aluminum phosphate binder in situ. In accordance withanother embodiment of the present invention, increased strength isachieved by including alumina, and an aluminum silicate bearingmaterial, such as clay, in the refractory composition to form the insitu aluminum phosphate bond from the reaction of phosphoric acid andaluminum silicate. The aluminum phosphate should be provided in thecomposition in an amount of about 5% to about 70% by weight of the bonedry composition and the phosphoric acid should be included in an amountin the range of about 1% to about 10% based on the weight of the bonedry composition to provide the suprisingly new and unexpected shelf lifeto the refractory composition. It has been found that the phosphoricacid will partially react with the alumina or aluminum silicate of therefractory composition and partially provide wetting to the refractoryramming mix. The phosphoric acid wetting does not deliteriously effectthe aluminum phosphate chemical binder. In fact, surprisingly, it hasbeen found that greater strength is achieved in the refractorycomposition when both the aluminum phosphate and the phosphoric acid areincluded together than in prior art refractory composition utilizing thealuminum phosphate binder which is added either as aluminum phosphate oras phosphoric acid for reaction with alumina in situ. Accordingly,suprisingly longer shelf lives and suprisingly greater crushingstrengths are achieved by including both aluminum phosphate andphosphoric acid, in the amounts specified, in the refractory rammingmix.

In accordance with another embodiment of the present invention, thealuminum phosphate and phosphoric acid together are particularly usefulin a refractory ramming mix composition containing a heat insulator suchas perlite, vermiculite, diatomaceous earth, expanded clay, flourspar,or an additive which is intended to be burned out to leave a void spaceat the intended use of the refractory, such as wood flour, sawdust,burnable fibers and the like. Refractory ramming mixes containing atleast 5% of such an insulating component inherently are weaker, but areunexpectedly strengthened in accordance with the present invention byincluding both aluminum phosphate and phosphoric acid chemical binders.

Accordingly, an object of the present invention is to provide arefractory material based on alumina, aluminum silicate or mixturesthereof having a much longer shelf life than similar prior artrefractory materials.

Another object of the present invention is to provide a refractorymaterial based upon alumina, aluminum silicate or mixtures thereof whichretains its plasticity or workability for unexpectedly long periods oftime before curing.

Another object of the present invention is to provide a refractoryramming mix based upon alumina, aluminum silicate or mixtures thereofwherein part of the binder is included in the refractory mix as aluminumphosphate and a portion of the binder is added as phosphoric acid forreaction in situ as the ramming mix is cured to provide a strongerrefractory material having a longer shelf life.

Another object of the present invention is to provide a refractory,insulating material based upon alumina, aluminum silicate or mixturesthereof and including an insulating material selected from the groupconsisting of perlite, vermiculite, diatomaceous earth, expanded clayand mixtures thereof.

Another object of the present invention is to provide a refractoryramming mix based upon alumina, aluminum silicate or mixtures thereofincluding expanded clay and a material such as perlite, vermiculite,sawdust or other material which will burn out at the temperatureencountered in the environment of use leaving voids in the refractorymaterial for the purpose of insulation to provide a refractory capableof withstanding temperatures of 2500-3500° F. while retainingunexpectedly superior strength characteristics.

Another object of the present invention is to provide a dry method andrefractory article based upon magnesium oxide or mixtures of magnesiumoxide with chrome ores to provide a basic refractory material.

Another object of the present invention is to provide a basic refractorymaterial based upon magnesium oxide or mixtures of magnesium oxide withchrome materials which can be mixed with water at the job site toprovide a plastic or pastey consistency so that the basic refractorymaterial can be trowled or otherwise suitably applied in place to act asa lining for a furnace or other high temperature environment therebyforming a magnesium aluminum phosphate chemical bond in situ.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, a refractory ramming mixhaving a plastic or pastey consistency chemically bonded by acombination of liquid aluminum phosphate and an in situ binder formed bythe reaction of phosphoric acid and alumina or an aluminum silicatebearing material, such as bentonite clay, is capable of withstandingtemperatures in the area of 2,000-3,500° F. The plastic, chemicallybonded refractory ramming mix has a suprisingly unexpected shelf life inthe range of 3 months to more than one year and is stronger than priorart refractory ramming mixes which utilize either prereacted aluminumphosphate or the in situ reaction of phosphoric acid with alumina oraluminum silicate.

In accordance with an important embodiment of the present invention, theplastic refractory composition includes an insulating material such asperlite, vermiculite, or diatomaceous earth to provide an insulating,refractory plastic composition containing both liquid aluminum phosphateand a in situ reaction product binder formed from the reaction ofphosphoric acid with alumina or an aluminum silicate containing materialsuch as clay. It has been found that both increased shelf life andincreased strength are achieved in accordance with the presentinvention, even with the inclusion of a substantial percentage, forexample 5-60%, of the insulating material. Higher temperature resistancecan be achieved by using what is commonly known as bubble alumina--analumina containing void spaces or air pockets therein, or mixing aburnable material, such as sawdust, with alumina or aluminum silicate sothat when fired, the burnable material contained in the alumina oraluminum silicate will pyrolyze leaving void spaces to increase itsinsulating properties.

In accordance with one embodiment of the present invention, therefractory composition includes liquid aluminum phosphate in an amountof 5-70%; a refractory material comprising alumina, aluminum silicate ormixtures thereof in an amount of 2-94%; and phosphoric acid in an amountof 1-10% by weight of the total composition. Surprisingly, it has beenfound that this refractory composition using both liquid aluminumphosphate and phosphoric acid has unusually long, unexpected shelf livesof 3 months to more than 1 year as a result of the chemical bondingbeing formed partially in situ as the reaction product of the freephosphoric acid with the alumina or aluminum silicate refractorymaterial. The shelf life is not only unexpectedly increased, but theproduct is stronger than if the refractory material is chemically bondedby aluminum phosphate alone or by completely forming the bond in situ byreaction of phosphoric acid with alumina or alumina silicate. It wouldbe expected that the partial in situ binding as a result of the reactionbetween phosphoric acid and alumina or aluminum silicate would cause adecrease in the shelf life of the refractory ramming mix since thereaction is exothermic and would inherently drive off some of themoisture from the ramming mix slab. However, unexpectedly, the rammingmix composition of this embodiment of the present invention hasunexpectedly long shelf lives of three months to more than one year. Infact, one test sample remains in a rammable or poundable plasticconsistency after being sliced to predetermined dimensions more than oneyear ago.

It is theorized that the liquid aluminum phosphate and the liquidphosphoric acid combine to provide a unique and unexpected wettingaction to the refractory compositions of the present invention enablingthe refractory ramming composition to remain wet and suitable forramming into position for unexpected periods of time. Liquid aluminumphosphate alone, or phosphoric acid alone for in situ reaction toprovide aluminum phosphate, provide shelf lives of at most about 3weeks. Additionally, the combination of both aluminum phosphate andphosphoric acid provide a stronger product apparently resulting from thein situ partial bond by the reaction of phosphoric acid with eitheralumina or aluminum silicate. In either case, the reaction produces anin situ aluminum phosphate bond. Phosphoric acid in an amount of atleast one percent should be included in the refractory ramming mix inorder to achieve the in situ bonding and the unexpected shelf life andstrength in the refractory product while more than 10% phosphoric acidmay create a supersaturated mix which is difficult or impossible tocure.

In accordance with another important feature of the present invention,it is unnecessary to add any water to the refractory ramming mix. Watermay be added in an amount of 1-20% of the total weight of thecomposition if it is necessary in order to achieve a proper consistencyor workability so that a plastic or pastey composition can be spread toa desired shape, but the liquid aluminum phosphate and the freephosphoric acid contained in the refractory composition of the presentinvention is generally sufficient to provide the proper consistency andworkability, particularly where the aluminum phosphate is contained inthe composition in an amount in the range of 20-70% by weight.

Generally, some water in an amount for example 1% by weight of the totalcomposition is introduced into the mix with the phosphoric acid but itis otherwise unnecessary to add water for the purpose of plasticity orworkability in the composition. It has been found that the addition ofwater in the composition of the present invention will result in asomewhat weaker product due to voids contained in the refractorymaterial upon release of the water from the ramming mix, although voidsmay add further insulating characteristics to the refractorycomposition. Other refractory granular materials or ceramic fibers maybe added to the composition of the present invention for economicreasons or to improve the strength of the composition.

The alumina utilized in accordance with the composition of the presentinvention is a granular processed alumina which is relatively pure Al₂O₃. The alumina may be tabular to achieve a denser product or calcinedalumina and may include bubble alumina having a higher insulating value.For higher temperature resistance the alumina may be less dense calcinedalumina generally having a density on the order of 80-100 lbs. per cubicfoot, but since calcined alumina is not normally commercially availablein coarser grain sizes, it is generally preferred to include a mixtureof tabular alumina and calcined alumina, as disclosed in my prior U.S.Pat. No. 3,547,664. Generally, for the purpose of the present invention,higher temperature resistance can be achieved if at least a portion ofthe alumina has a particle size of -325 mesh.

Clay is useful in accordance with the composition of the presentinvention to aid in providing the requisite plasticity and workabilitynecessary for ramming and also may be used as a source of aluminumsilicate for reaction with the phosphoric acid to provide the in situaluminum phosphate binder. Any of the plastic clays or any other sourceof aluminum silicate may be used in accordance with the principles ofthe present invention. Generally, some clay should be present in orderto provide a thickening of the refractory composition to a pastey ormortar-like consistency. Kaolin clay, ball clay, bentonite and the likeserve as thickening agents in the initial sheeting out of the refractorycomposition of the present invention to a desired shape and, duringcuring, the clay or other source of aluminum silicate will react withthe free phosphoric acid in the mix to provide in situ bonding therebyachieving unexpectedly long shelf lives and strength in the compositionsof the present inventions.

To achieve the full advantage of the present invention, clay should beincluded in the refractory composition in an amount in the range ofabout 1 to about 30% by weight of the total composition to providethickening and an aluminum silicate source for reaction with thephosphoric acid. Other aluminum silicates may be used for reaction withphosphoric acid to provide the aluminum phosphate in situ binder. Thephosphoric acid included in the composition of the present inventionreacts not only with the alumina or aluminum silicate refractorymaterial but also with the clay component, when present, giving astronger bond to the product.

After the refractory composition of the present invention is spread intoa desired shape and sliced to predetermined dimensions, the clay orother source of aluminum silicate begins to react with the phosphoricacid. Once the refractory slabs or slices are rammed or pounded intoplace, the material is heated to a temperature of at least 450° F. tocomplete the reaction between the aluminum silicate or clay and thephosphoric acid, to dry the refractory material and to irreversibly setthe phosphoric acid-aluminum silicate reaction. Thereafter the materialis fused at a temperature of about 4,000° F. to create the ceramic bond.

It has been found that by including an insulating material in therefractory composition of the present invention, an exceptionally hightemperature resistance can be imparted to the composition whileproviding a composition with excellent strength and shelf life. Thefollowing examples show exemplary refractory material compositionshaving temperature resistance at various, indicated levels. Thepercentages indicated in the examples are percent by weight of the totalcomposition:

    ______________________________________                                        EXAMPLE 1 - 2000° F.                                                   Liquid aluminum phosphate                                                                             5-70%                                                 Aluminum silicate       10-89%                                                Phosphoric acid         1-10%                                                 Perlite, vermiculite or diatomaceous earth                                                            5-40%                                                 EXAMPLE 2 - 2500° F.                                                   Liquid aluminum phosphate                                                                             5-70%                                                 Alumina                 20-88%                                                Phosphoric acid         1-10%                                                 Perlite, vermiculite or diatomaceous earth                                                            5-40%                                                 Fibers burnable below 2500° F., for                                                            5-20%                                                 example, cotton or polyester fibers                                           EXAMPLE 3 - 3000° F.                                                   Liquid aluminum phosphate                                                                             5-70%                                                 Alumina                 25-88%                                                Phosphoric acid         1-10%                                                 Expanded clay, i.e. bentonite                                                                         1-30%                                                 Perlite, vermiculite or diatomaceous earth                                                            5-40%                                                 EXAMPLE 4 - 3000° F.                                                   Liquid aluminum phosphate                                                                             5-70%                                                 Bubble alumina and expanded clay                                                                      25-88%                                                i.e. bentonite, in weight proportions                                         of 1:2 to 2:1                                                                 Phosphoric acid         1-10%                                                 Perlite, vermiculite or diatomaceous earth                                                            5-20%                                                 fibers burnable below 3000° F.                                         Kaolin, ball clay or mixtures                                                                         1-30%                                                 EXAMPLE 5 - 3500° F.                                                   Liquid aluminum phosphate                                                                             5-70%                                                 Bubble alumina          10-78%                                                Finely ground alumina (-325 mesh)                                                                     10-78%                                                Phosphoric acid         1-10%                                                 Perlite, vermiculite or diatomaceous earth                                                            5-40%                                                 Bentonite               1-30%                                                 EXAMPLE 6                                                                     Liquid aluminum phosphate                                                                             50%                                                   Alumina -100 Mesh       7%                                                    -325 Mesh               7%                                                    Phosphoric acid (80% H.sub.3 PO.sub.4)                                                                2%                                                    Expanded Kaolin Clay    15%                                                   Expanded perlite*       16%                                                   Bentonite               1%                                                    Ball clay               2%                                                    *     -10 Mesh      -20 Mesh     -200 Mesh                                    Perlite                                                                             8%            4%           4%                                           EXAMPLE 7                                                                     Liquid aluminum phosphate                                                                             35%                                                   Alumina -100 Mesh       5%                                                    -325 Mesh               10%                                                   Phosphoric acid (80% H.sub.3 PO.sub.4)                                                                5%                                                    Expanded Kaolin Clay    10%                                                   Expanded perlite*       10%                                                   Bentonite               15%                                                   Ball clay               10%                                                   *     -10 Mesh      -20 Mesh     -200 Mesh                                    Perlite                                                                             2%            6%           2%                                           EXAMPLE 8                                                                     Liquid aluminum phosphate                                                                             40%                                                   Alumina -100 Mesh       10%                                                   -325 Mesh               10%                                                   Phosphoric acid (80% H.sub.3 PO.sub.4)                                                                4%                                                    Expanded perlite*       20%                                                   Expanded ball clay      8%                                                    Clay - Bentonite        2%                                                    Ball clay               1%                                                    Ceramic fibers:         5%                                                    *     -10 Mesh      -20 Mesh     -200 Mesh                                    Perlite                                                                             5%            5%           10%                                          ______________________________________                                    

In accordance with another important embodiment of the presentinvention, a basic refractory composition is prepared based uponmagnesium oxide, magnesite, dolomite, chromemagnesite, or mixturesthereof. To form a basic refractory material chemically bound withaluminum phosphate which reacts with the magnesium oxide when wet toform magnesium aluminum phosphate.

In accordance with an important feature of this embodiment of thepresent invention, it has been found that the refractory composition canbe initially made in a dried form prior to the addition of the wateroxide so that shelf life is not a problem with the M_(g) O basedcomposition of the present invention. In accordance with this embodimentof the present invention, the aluminum phosphate is added to thecomposition in dried form. For example, phosphoric acid may be reactedwith an aluminum silicate clay, for example bentonite, and the reactedclay dried at a temperature at about 300-600° F. to remove substantiallyall moisture. Dried magnesite or other dried magnesium oxide containingmaterial can be added to the composition together with any otherfillers, insulating materials and the like and water can be added to thecomposition at the job site in an amount suitable for proper consistencyand workability prior to troweling or otherwise suitably applying thecomposition as a liner, industrial furnace cover and the like. Suitableexamples of basic refractory compositions of the present invention,based upon M_(g) O, are as follows:

    ______________________________________                                        EXAMPLE 9                                                                     Dried aluminum phosphate 5-70%                                                A dried source of magnesium oxide,                                                                     20-96%                                               for example magnesite, chrome magnesite,                                      dolomite or mixtures thereof                                                  Clay                     1-30%                                                EXAMPLE 10                                                                    Dried aluminum phosphate 5-70%                                                Dried magnesium oxide source of Example 6                                                              20-93%                                               Clay                     1-30%                                                Phosphoric acid (the phosphoric acid can be                                                            1-10%                                                added at the time of water addition)                                          EXAMPLE 11                                                                    Dried aluminum phosphate 5-70%                                                Dried magnesium oxide source of Example 6                                                              20-89%                                               Clay                     1-30%                                                Perlite, vermiculite or diatomaceous earth                                                             5-40%                                                EXAMPLE 12                                                                    Dried aluminum phosphate 5-70%                                                Dried magnesium oxide source of Example 6                                                              20-84%                                               Expanded clay, i.e. bentonite                                                                          1-30%                                                Perlite, vermiculite or diatomaceous earth                                                             5-40%                                                Fibers burnable below 2000° F.                                                                  5-20%                                                ______________________________________                                    

Water is added to the basic M_(g) O based refractory compositions of thepresent invention in an amount of 1-20% by weight of the driedcomposition to provide a plastic or workable basic refractorycomposition and the reaction between aluminum phosphate and the M_(g) Oto form a magnesium aluminum phosphate bond. Phosphoric acid can beadded to the basic M_(g) O based composition to provide greaterstrength, but generally shelf life increase is not of consequence in theM_(g) O based refractory since it will be wetted at the job site andimmediately disposed in place. Further, if phosphoric acid is addedtogether with the aluminum phosphate during manufacture of the basic drycomposition, the phosphoric acid and aluminum phosphate should be dryprior to the addition of magnesium oxide to prevent initiation of thereaction.

It has been found that when a insulating material such as perlite,vermiculite or diatomaceous earth is included in the composition in anamount of at least 5% by weight of the total composition, the refractorycomposition should not be in direct contact with a liquid metal due tothe lower density of the insulating, refractory compositions. However,temperatures up to about 3500° F. do not deliteriously affect suitablerefractory compositions of the present invention.

The refractory compositions of the present invention are useful inessentially all of the uses well known in the refractory art,particularly when an insulating material is included for temperatureenvironments over 2000° F. Examples of suitable applications for therefractory materials of the present invention include original furnaceliners, soaking pit walls, reheat furnace walls and roof liners,induction furnace covers, as a back-up lining for the aforementionedapplications to act as an insulating lining behind a prior artrefractory lining; refractory linings for boilers, and linings forforging furnaces. Other uses will be apparent to those skilled in therefractory art.

I claim:
 1. A refractory composition having an increased shelf lifecomprising:

    ______________________________________                                        Aluminum phosphate      5-70%;                                                A refractory material selected                                                                        2-94%; and                                            from the group consisting of                                                  alumina, aluminum silicate,                                                   and mixtures thereof                                                          Phosphoric acid         1-10%.                                                ______________________________________                                    


2. The refractory composition of claim 1 comprising:

    ______________________________________                                        Aluminum phosphate    20-60%;                                                 Alumina               20-60%; and                                             Phosphoric Acid        2-10%.                                                 ______________________________________                                    


3. The refractory material of claim 1 further including water in theamount of 1-20% based upon the total weight of aluminum phosphate,refractory material and phosphoric acid.
 4. The refractory compositionof claim 1 comprising:

    ______________________________________                                        Aluminum phosphate        5-70%;                                              Alumina, aluminum silicate or                                                                           2-89%;                                              mixtures thereof                                                              Phosphoric acid           1-10%;                                              An insulating material selected                                                                         5-60%                                               from the group consisting of                                                  perlite, vermiculite, diatomaceous                                            earth, flourspar, wood flour, wood                                            dust, clay, ceramic fibers,                                                   light weight grog, and expanded                                               shell.                                                                        ______________________________________                                    


5. The refractory composition of claim 4 wherein said insulatingmaterial is selected from the group consisting of perlite, vermiculiteand diatomceous earth.
 6. The refractory material of claim 1 comprising:

    ______________________________________                                        Aluminum phosphate    20-70%;                                                 Alumina               20-77%;                                                 Aluminum silicate     1-30%; and                                              Phosphoric acid       2-8%.                                                   ______________________________________                                    


7. The refractory material of claim 6 comprising:

    ______________________________________                                        Aluminum phosphate     20-70%;                                                Alumina                20-75%;                                                Clay                   1-30%;                                                 Phosphoric acid        2-8%; and                                              Fibers burnable at or below                                                                          1-15%.                                                 2000° F.                                                               ______________________________________                                    


8. The refractory material of claim 1 comprising:

    ______________________________________                                        Aluminum phosphate      20-70%;                                               Alumina                 20-63%;                                               Aluminum silicate       1-30%;                                                Phosphoric acid         1-10%; and                                            An insulating material selected                                                                       5-60%.                                                from the group consisting of                                                  perlite, vermiculite and                                                      diatomaceous earth                                                            ______________________________________                                    


9. The refractory composition of claim 4 comprising:

    ______________________________________                                        Liquid aluminum phosphate                                                                             20-70%;                                               Alumina, aluminum silicate or                                                                         2-69%;                                                mixtures thereof                                                              Phosphoric acid         1-10%; and                                            Expanded clay           10-60%.                                               ______________________________________                                    


10. A refractory composition having an increased shelf life comprising:

    ______________________________________                                        Liquid aluminum phosphate                                                                             5-70%;                                                Alumina, aluminum silicate or                                                                         2-93%;                                                mixtures thereof                                                              Phosphoric acid         1-10%; and                                            Expanded clay           1-30%.                                                ______________________________________                                    


11. The refractory composition of claim 10 comprising:

    ______________________________________                                        Liquid aluminum phosphate                                                                             10-50%;                                               Alumina, aluminum silicate or                                                                         20-84%;                                               mixtures thereof                                                              Phosphoric acid         1-10%; and                                            Expanded clay           5-20%.                                                ______________________________________                                    


12. The refractory composition of claim 11 comprising:

    ______________________________________                                        Liquid aluminum phosphate                                                                             10-30%;                                               Alumina                 2-93%;                                                Phosphoric acid         1-10%; and                                            Expanded clay           5-20%,                                                ______________________________________                                    

wherein 20-60% by weight of said alumina is alumina ground to -325 meshand 40-80% of said alumina is bubble alumina.
 13. The refractorycomposition of claim 12 wherein said bubble alumina is calcined alumina.14. The refractory composition of claim 12 wherein said clay is amontmorillonite clay.
 15. The refractory composition of claim 11 whereinsaid clay is bentonite.
 16. The refractory composition of claim 11further including water in an amount of 1-20% based upon the totalweight of aluminum phosphate, alumina, phosphoric acid and clay.
 17. Arefractory furnace lining disposed against an interior furnace wall orinterior furnace conduit comprising:

    ______________________________________                                        Aluminum phosphate      3-70%                                                 A refractory material selected                                                                        2-94%; and                                            from the group consisting of                                                  alumina, aluminum silicate,                                                   and mixtures thereof                                                          Phosphoric acid         1-10%.                                                ______________________________________                                    


18. The refractory furnace lining disposed against an interior furnacewall or interior furnace conduit of claim 17 comprising:

    ______________________________________                                        Aluminum phosphate      20-70%;                                               Alumina, aluminum silicate or                                                                         2-64%;                                                mixtures thereof                                                              Clay                    5-60%; and                                            An insulating material selected                                                                       10-60%.                                               from the group consisting of                                                  perlite, vermiculite, and                                                     diatomaceous earth                                                            ______________________________________                                    


19. The article of claim 17 comprising:

    ______________________________________                                        Aluminum phosphate    20-60%;                                                 Alumina               20-60%; and                                             Phosphoric Acid       2-10%.                                                  ______________________________________                                    


20. The article of claim 17 comprising:

    ______________________________________                                        Aluminum phosphate      5-70%;                                                Alumina, aluminum silicate or                                                                         2-89%;                                                mixtures thereof                                                              Phosphoric acid         1-10%; and                                            An insulating material selected                                                                       5-60%.                                                from the group consisting of                                                  perlite, vermiculite, diatomaceous                                            earth, flourspar, wood flour, wood                                            dust, clay, ceramic fibers, fibers                                            burnable below 3000° F., light                                         weight grog, and expanded shell                                               ______________________________________                                    